The Effects of Sleep Duration on Motor Performance and Mood

While there has been an abundant amount of research done on the effects of sleep deprivation on human functioning, relatively little has been done on the effects of extended sleep. This study investigated both ends of the sleep spectrum, it looked at how both sleep deprivation and extended sleep affect human functioning, specifically motor performance and mood. I hypothesized that there is an inverted u-shaped relationship between sleep duration and motor performance as well as between sleep duration and mood. Results of this study could help athletes prepare their bodies for peak performance, contribute knowledge to a very little researched portion of sleep studies, and add to the discussion on the function of sleep. Carleton College students were used as subjects in this experiment. On a Tuesday night subjects slept an average amount of sleep. The following day (Wednesday) they completed a series of tests and surveys that examined sleepiness, mood, strength, coordination, and reaction time. The following Friday subjects slept two hours more, two hours less, or the same amount as they did on Tuesday night. Saturday they came into the lab to complete the same series of tests and surveys. I hypothesized that those in both the extended group and deprivation group would perform significantly poorer on Saturday and report higher levels of fatigue and negative moods. Statistical analyses (the Kruskal-Wallis One-Way ANOVA, Wilcoxin-Mann-Whitney Test, and Wilcoxon Signed-Rank Test were used) showed that sleepiness level was the only variable significantly affected by sleep manipulation. The deprivation group reported significantly higher levels of sleepiness on Saturday as compared to Wednesday. They also reported significantly higher levels of sleepiness on Saturday as compared to both the control and extended groups. These results could suggest that humans are highly resilient animals or that two hours of sleep manipulation is not a large enough difference in sleep duration to show any significant changes in functioning. Additionally, the data for some of the factors in the extended and deprived groups were highly variably, suggesting that there might be a group of people greatly affected by sleep manipulation and others that are not so affected. Future studies could be done with a larger sample size in an effort to unmask these subgroups